/*
 [The "BSD license"]
 Copyright (c) 2011 Terence Parr
 All rights reserved.

 Redistribution and use in source and binary forms, with or without
 modification, are permitted provided that the following conditions
 are met:

 1. Redistributions of source code must retain the above copyright
    notice, this list of conditions and the following disclaimer.
 2. Redistributions in binary form must reproduce the above copyright
    notice, this list of conditions and the following disclaimer in the
    documentation and/or other materials provided with the distribution.
 3. The name of the author may not be used to endorse or promote products
    derived from this software without specific prior written permission.

 THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

package org.antlr.v4.runtime.tree.gui;

/** Font metrics.  The only way to generate accurate images
 *  in any format that contain text is to know the font metrics.
 *  Specifically, we need to know the width of every character and the
 *  maximum height (since we want all characters to fit within same line height).
 *  I used ttf2tfm to dump the font metrics from Mac TrueType fonts and
 *  then converted that to a Java class for use in a PostScript generator
 *  for trees. Commands:
 *
 * 		$ ttf2tfm /Library/Fonts/Arial\ Black.ttf > metrics
 *
 * 	Then run metrics into python code after stripping header/footer:
 *
 	 #
	 # Process lines from ttf2tfm that look like this:
 	 # Glyph  Code   Glyph Name                Width  llx    lly      urx    ury
 	 # ------------------------------------------------------------------------
	 #     3  00020  space                       333  0,     0 --     0,     0
     #
	 lines = open("metrics").read().split('\n')
	 print "public class FontName {"
	 print "    {"
	 maxh = 0;
	 for line in lines[4:]: # skip header 0..3
			 all = line.split(' ')
			 words = [x for x in all if len(x)>0]
			 ascii = int(words[1], 16)
			 height = int(words[8])
			 if height>maxh: maxh = height
			 if ascii>=128: break
			 print "        widths[%d] = %s; // %s" % (ascii, words[3], words[2])

	 print "        maxCharHeight = "+str(maxh)+";"
	 print "    }"
	 print "}"

 	Units are 1000th of an 'em'.
 */
public abstract class BasicFontMetrics {
	public static final int MAX_CHAR = '\u00FF';
	protected int maxCharHeight;
	protected int[] widths = new int[MAX_CHAR+1];

	public double getWidth(String s, int fontSize) {
		double w = 0;
		for (char c : s.toCharArray()) {
			w += getWidth(c, fontSize);
		}
		return w;
	}

	public double getWidth(char c, int fontSize) {
		if ( c > MAX_CHAR || widths[c]==0 ) return widths['m']/1000.0; // return width('m')
		return widths[c]/1000.0 * fontSize;
	}

	public double getLineHeight(int fontSize) {
		return maxCharHeight / 1000.0 * fontSize;
	}
}
